Yu Feng Zhang

Technology Study of Polypropylene Hollow Fiber Membranes-Like Artificial Lung Made by the Melt-Spinning and Cold-Stretching Method

Artificial lung also called as oxygenator which performs a function of exchanging O2 and removing CO2 from blood. Due to its good performance at the exchange area, oxygenation, etc, hollow fiber membranes have become the main research direction of artificial lung. Polypropylene (pp) hollow fiber membranes made by the melt-spinning and cold-stretching methods (MSCS) in this study. Through the research on the membrane manufacture process and technology optimization to prepare suitable membrane for artificially lung. The performance of membrane was affected by the melt-draw ratio and spinning temperature, annealing temperature, and the proportional relations of cold stretch with hot stretch. The results of the study show that improve melt-draw ratio, select the appropriate annealing conditions and the reasonable ratio of hot stretch with cold stretch can effectively increase the air flux of pp hollow fiber membrane.

Poly(vinylidene fluoride) (PVDF) Membrane Preparation with an Ionic Liquid via Thermally Induced Phase Separation Melt Technology

Poly(vinylidene fluoride) (PVDF)/1-butyl-2,3-dimethylimidazolium Tetrafluoroborate ([BMMIm][BF4]) flat sheet membranes were made via thermally induced phase separation (TIPS) melt technology, and [BMMIm][BF4]) was used as a diluent. The prepared membranes were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) and etc. Furthermore, [BMMIm][BF4] as a liquid-diluent was effectively recovered by vacuum distillation. In conclusion, this work may provide a green and sustainable preparation method to produce PVDF membranes via TIPS.

Preparation of a Novel Composite Nanofiltration Membrane

PDMAEMA/PSF nanofiltration (NF) membranes were prepared through interfacial polymerization of poly [2-(N,N-dimethyl amino) ethyl methacrylate](PDMAEMA) on porous polysulfone (PSF) substrate membranes. The effects of aqueous solution’s pH and crosslinking time and on separation performances of the PDMAEMA/PSF NF membrane were investigated. The results show that the rejection and flux of the PDMAEMA/PSF NF membrane show pH-sensitive behavior in NF process. Importantly, the membrane show a different separation between inorganic salts and small organic molecules.

Microporous Polypropylene Hollow Fiber Membrane Application in Membrane Oxygenator Model

In order to test the performance of the resulting membrane oxygenator, a model was constructed to simulate the inner and extracorporeal gas exchange of the human body. The oxygenation capacity of the membrane oxygenator was studied using fresh bovine blood with added anticoagulants as the test medium. The oxygenation performance of the prepared membrane was equal to that of the commercial membrane. After six hours of operation, the oxygen saturation (SaO2) was above 95%, and the partial pressure of oxygen (PaO2) was over 13.5 kPa (100 mmHg). This model was constructed in accordance with the basic principles of extracorporeal circulation, and could be used to investigate the oxygenation performance of a membrane oxygenator, as well as to study the basic principles of extracorporeal circulation.

Study of Forward Osmosis Membrane Bioreactor

A novel submerged forward osmosis membrane bioreactor (FOMBR) is presented in this study. The selection of optical draw solutions for forward osmosis (FO) applications was developed and the Na2SO4 solution was found to be the most appropriate draw solution among five draw solutions for FO applications. The properties of two hollow fiber composite FO membranes, designated membranes A and B, which consist of an active layer formed atop a support layer, were prepared and utilized. Meanwhile, the water flux and removal efficiencies were evaluated in FO mode. Both of the FO membranes were found to reject greater than 95% of COD and 85% of NH3-N. Water flux changes suggested a better application with membrane A than membrane B for FOMBR.

Morphology and Properties of a Series of PVDF Blend Membranes

In this article, a series of the PVDF/PPTA blend membranes with porous structure and excellent performance were successfully prepared by the phase transformation method. The effect of the mass ratio of W(PVDF)/W(PPTA) was systematically investigated.The morphology of the blend membranes were examined using scanning electron microscope (SEM). The permeation performance was characterized by measuring pure water flux. Meanwhile, the mechanical properties of membranes were researched. The experiment results confirmed that the blending ratio is a major factor to influence the structure and performance of PVDF/PPTA blend membrane. The blend membranes possess much better permeability than pure PVDF membrane and fairly good the mechanical properties especially for the membrane made by PVDF : PPTA=6 : 1.

Study on the Treatment of High Salinity Oil Waste Water by Reverse Osmosis Technology

Taking reverse osmosis (RO) technology for the treatment of high salt containing oil waste water as the example, this study investigated the relationship between the pressure and the permeate flux, the stability of the membrane module and the membrane cleaning cycle. The results show the feasibility of RO technology for the treatment of high salt containing oil waste water.

Study on the Properties of PVDF/LCP Blending Membranes

In this study, polyvinylidene fluoride/liquid crystal polymer (PVDF/LCP) blending membranes were prepared via phase-inversion. LCP is ethyl cellulose (EC) dissolved into acrylic acid (AA). The properties of these blends were measured by differential scanning calorimeter (DSC) and polarizing microscope. The results indicate that LCP formed at the concentration of 0.60g/ml and the blends begin to be observed the presence of liquid crystal. Moreover, at a certain temperature range, higher temperature can quicken the formation of liquid crystal. With the adding of LCP, the cholesteric liquid crystal can be still retained in the blending membranes, but the solution enthalpy decreased.

Study on the Calamine/Sodium Alginate Modified Viscose Fiber

In this article we successfully prepared calamine / sodium alginate viscose fiber. Good dispersion and stability of the modified solution was prepared by dispersing calamine in alkaline solution of sodium alginate, and then mixed it with viscose spinning solution by spinning injection methods. Moreover, the stability of calamine / sodium alginate solution, the effect of concentration of calamine on the fiber properties is studied in this paper. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and physical mechanical performance are test to characterize the structure and the performance of the calamine / sodium alginate viscose fiber.